Phenomenological modeling of photoemission spectra in strongly correlated electron systems

A phenomenological approach is presented that allows one to model, and thereby interpret photoemission spectra of strongly correlated electron systems. A simple analytical formula for the self-energy is proposed. This self-energy describes both the coherent and incoherent parts of the spectrum (quasiparticle and Hubbard peaks, respectively). Free parameters in the expression axe determined by fitting the density of states to experimental photoemission data. An explicit fitting is presented for the La1-xSrxTiO3 system with 0.08 less than or equal to x less than or equal to 0.38. In general, our phenomenological approach provides information on the effective mass, the Hubbard interaction, and the spectral weight distribution in different parts of the spectrum. Limitations of this approach axe also discussed.